Primary care settings are ideal for initiating advance care planning (ACP) conversations and assessing palliative and supportive care needs. However, time constraints and a lack of confidence to sensitively and efficiently initiate such discussions are noted barriers. The Advance Project implemented a national multicomponent training package to support Australian general practice nurses (GPNs) to work with GPs to initiate ACP and palliative care conversations in their practice. This paper reports on semistructured interviews conducted with 20 GPNs to explore barriers and facilitators to implementing the Advance Project model. Participants identified a range of factors that affected implementation, including lack of time, limited support from colleagues, lack of knowledge about systems and funding processes in general practice and a need for better alignment of the Advance Project resources and practices with general practice information management platforms. Barriers related to professional roles, particularly the lack of clarity and/or limitations in the scope of practice of GPNs, highlighted the importance of defining and supporting the roles that different primary health practice staff could play to support implementation of the model. The findings underline the need for complementary training in the Advance Project model for GPs and practice managers to enable a team-based approach to implementation.